#!/usr/bin/env node

'use strict';

/* globals Set */
/*!
 * Script to update version number references in the project.
 * Copyright 2015 Twitter, Inc.
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 */
var fs = require('fs');
var path = require('path');
var sh = require('shelljs');
sh.config.fatal = true;
var sed = sh.sed;

// Blame TC39... https://github.com/benjamingr/RegExp.escape/issues/37
RegExp.quote = function(string) {
	return string.replace(/[-\\^$*+?.()|[\]{}]/g, '\\$&');
};
RegExp.quoteReplacement = function(string) {
	return string.replace(/[$]/g, '$$');
};

var DRY_RUN = false;

function walkAsync(directory, excludedDirectories, fileCallback, errback) {
	if(excludedDirectories.has(path.parse(directory).base)) {
		return;
	}
	fs.readdir(directory, function(err, names) {
		if(err) {
			errback(err);
			return;
		}
		names.forEach(function(name) {
			var filepath = path.join(directory, name);
			fs.lstat(filepath, function(err, stats) {
				if(err) {
					process.nextTick(errback, err);
					return;
				}
				if(stats.isSymbolicLink()) {
					return;
				} else if(stats.isDirectory()) {
					process.nextTick(walkAsync, filepath, excludedDirectories, fileCallback, errback);
				} else if(stats.isFile()) {
					process.nextTick(fileCallback, filepath);
				}
			});
		});
	});
}

function replaceRecursively(directory, excludedDirectories, allowedExtensions, original, replacement) {
	original = new RegExp(RegExp.quote(original), 'g');
	replacement = RegExp.quoteReplacement(replacement);
	var updateFile = !DRY_RUN ? function(filepath) {
		if(allowedExtensions.has(path.parse(filepath).ext)) {
			sed('-i', original, replacement, filepath);
		}
	} : function(filepath) {
		if(allowedExtensions.has(path.parse(filepath).ext)) {
			console.log('FILE: ' + filepath);
		} else {
			console.log('EXCLUDED:' + filepath);
		}
	};
	walkAsync(directory, excludedDirectories, updateFile, function(err) {
		console.error('ERROR while traversing directory!:');
		console.error(err);
		process.exit(1);
	});
}

function main(args) {
	if(args.length !== 2) {
		console.error('USAGE: change-version old_version new_version');
		console.error('Got arguments:', args);
		process.exit(1);
	}
	var oldVersion = args[0];
	var newVersion = args[1];
	var EXCLUDED_DIRS = new Set([
		'.git',
		'node_modules',
		'vendor'
	]);
	var INCLUDED_EXTENSIONS = new Set([
		// This extension whitelist is how we avoid modifying binary files
		'',
		'.css',
		'.html',
		'.js',
		'.json',
		'.less',
		'.md',
		'.nuspec',
		'.ps1',
		'.scss',
		'.txt',
		'.yml'
	]);
	replaceRecursively('.', EXCLUDED_DIRS, INCLUDED_EXTENSIONS, oldVersion, newVersion);
}

main(process.argv.slice(2));